51891295689 has 12 divisors (see below), whose sum is σ = 75168866500. Its totient is φ = 34495071264.

The previous prime is 51891295679. The next prime is 51891295721. The reversal of 51891295689 is 98659219815.

51891295689 is a `hidden beast` number, since 51 + 8 + 9 + 12 + 9 + 568 + 9 = 666.

51891295689 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in 2 ways, for example, as 19766110464 + 32125185225 = 140592^2 + 179235^2 .

It is not a de Polignac number, because 51891295689 - 2⁸ = 51891295433 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (51891295619) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 8257174 + ... + 8263455.

Almost surely, 2^51891295689 is an apocalyptic number.

It is an amenable number.

51891295689 is a deficient number, since it is larger than the sum of its proper divisors (23277570811).

51891295689 is a wasteful number, since it uses less digits than its factorization.

51891295689 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 16520984 (or 16520981 counting only the distinct ones).

The product of its digits is 13996800, while the sum is 63.

The spelling of 51891295689 in words is "fifty-one billion, eight hundred ninety-one million, two hundred ninety-five thousand, six hundred eighty-nine".